A model estimating the contributions of sulfur compounds by natural and human activities, and the rate of removal of sulfur from the atmosphere, is based on a review of the existing literature. Areas requiring additional research are identified. (AL)

The properties of the weak force between the subatomic particles is described. The weak force is observed in the form of nuclear beta radioactivity. Applications are given to terrestrial and extraterrestrial phenomena. (TS)

Describes the structure, availability, and use of a computer program designed for a wide variety of data of curvefitting and equation-solving problems, including both linear and non-linear problems. (PR)

Examines the model of interacting nerve systems based on a switching theory, which uses a mathematical structure familiar to many high school students and requires little knowledge of biology. Reviews the basic operation of nerves, and demonstrates how Boolean algebraic statements are applied to synaptic interactions. (PR)

A discussion of books, periodicals, instructional and supplementary materials that study the Negro within the context of American history. (JB)

Describes a model of an air pollution control strategy, closely integrated with urban and regional planning, based upon attaching well defined emission rights to each parcel of land in a region. (AL)